U.S. DEPARTMENT OF

ENERGY Energy Efficiency & Renewable Energy

Advanced Battery Material Research (BMR)Vehicle Technologies Office

FY 18 Milestones:•Development of well defined single crystal LLZO interfaces to

assess factors that govern the interfacial and bulk properties of the Li/LLZO system. • Investigate other relevant crystalline oxides and glassy

materials as a potential solid electrolytes. • Explore the interaction of solid electrolytes with well-

characteriaed cathode oxide materials (LiCoO2)FY18 Deliverables: Quarterly reports, new approaches for characterization and modeling interfaces Funding: — FY19: $400,000 FY18: $400,000 FY17: $400,000

Advancing Solid-State Interfaces in Li-ion Batteries

• Objective: Develop mechanically and chemically stable Li-selective solid “membranes” in organic electrolytes ( SLi-SM-EEL) and conductive solid electrolytes for a solid-state battery (SLi-SEL-SC ) capable of protecting the metal Li anode during the discharge process.

Impact:• Protective organic and inorganic compounds can lead

to enhanced stability of interface, improve Li ion interfacial transport, minimize dendrite formation and increase safety in Li ion batteries.

Accomplishments:• Developed state-of-the-art experimental and

computational techniques capable of exploring chemical stability and reactivity of SLi-SEL-SC systems.

• Established first ever stability-/reactivity-function relationships for studying interaction of Li metal anode with a model Nb doped SrTiO3 (STO) single crystal solid electrolyte.

• Used the knowledge from model systems to understand Li interaction with a real (Li6.5La3Zr1.5Nb0.5O12, LLZO) solid electrolyte.

• Understanding of morphological and chemical stability of Li-Nb:STO(hkl) and Li-Nb:LLZO via DFT calculations

Chemical and morphological interfacial interactions of Li with solid electrolytes : from model to real systems

PI/Co-PI: PI/Co-PI: Nenad M Markovic(ANL), Larry A. Curtiss ANL)

Model System

A - illustrates structural and chemical characterization of STO(001) surface both before and after Li deposition. B - illustrates Li interaction with Nb:LLZO system

(A) Real System(B)

U.S. DEPARTMENT OF

ENERGY Energy Efficiency & Renewable Energy

Advanced Battery Material Research (BMR)Vehicle Technologies Office

FY 17 Milestones:• Demonstrate full cells with NMC cathode• Demonstrate full cells with Sulfur cathode• Develop models to investigate interfacial transport for Li-S

and Li-NMC SSLiBs• Achieve full cell (Li-S or Li-NMC) performance of 350-450

Wh/kg and 200 cyclesFY17 Deliverables: Submission of 12 improved cells for government testing and evaluationFunding: — FY17: $401,634, FY16: $401,635 FY15: $409,608

OVERCOMING INTERFACIAL IMPEDANCE IN SOLID-STATEBATTERIES

Objective: Develop a multifaceted and integrated (experimental and computational) approach to reduce interfacial impedance of garnet-based solid-state Li ion batteries (SSLiBs). Impact:• Overcome primary issue with garnet electrolyte SSLiBs,

interfacial impedance, thus enabling an entirely new safer (non-flammable) battery platform

• Enable highest capacity Li-metal anodes with no dendrites for higher energy density batteries (~500 Wh/kg)

Accomplishments: (FY16)• First comprehensive investigation of interface

impedance in garnet based SSLiBs• Determined interfacial impedance as function of

electrolyte/electrode contact area in 3D controlled solid state structures

• Developed computational models to investigate interfacial ion transport with interlayers

• Developed multiple efficient interlayer solutions to decrease interfacial impedance

• Demonstrated low interfacial impedance (~10 Ω cm2) between both electrolyte and Li-metal anode and between electrolyte and cathode

Li-Metal Wetting of Solid-State ElectrolytePI/Co-PI: Eric Wachsman (UMD)/ Liangbing Hu (UMD) / Yifei Mo (UMD)

Developed surface treatment to allow Li-metal wetting thus dramatically reducing interfacial impedance

EXAMPLE